Sanofi-Aventis, a manufacturer of the swine flu vaccine, voluntarily recalled 800,000 doses intended for infants after tests revealed that the vaccine lost potency with time. The vaccine, distributed in pre-filled syringes and intended for children between the ages of 6 months and nearly three years, was recalled after tests showed that, while the vaccine was fully potent at initial release, the vaccine’s potency dropped by 12% in later analyses.
The vaccine being recalled is the only thimerosal-free version currently licensed for use in children ages 2 and younger, and may have already been given to some infants. Yet, health officials say there is little cause for alarm—vaccination guidelines for young children call for two doses, meaning that even if they were given a weaker version, together with a follow-up shot, the vaccine should offer adequate protection.